Some additional information:

To demonstrate the issue I have encountered, I took the code sample provided by Salesforce.com in their documentation: Using Dynamic References with Standard Objects. The code is located in the section titled: Using Dynamic References for a User-Customizable Page. Here is a link to the page: http://www.salesforce.com/us/developer/docs/pages/Content/pages_dynamic_vf_sample_standard.htm

I made two slight modifications:

1. Added a wrapper class around the field list. So, instead of a list of field names, we have a list of class objects that contain not only the API field name, but an additional attribute used for styling purposes.
2. Instead of using the Case object, I am using the Contact object with the ReportsToID reference field and associated ReportsTo.name and ReportsTo.email fields.

Here is the page definition:

<apex:page controller="DynamicCaseLoader"> 
<apex:form >

    <apex:repeat value="{!contactDetails}" var="contactObj">
        <apex:repeat value="{!contactFieldListObj}" var="cf">
	   <apex:outputPanel layout="block">    
    	        <apex:outputField value="{!contactObj[cf.fieldName]}"  />
	   </apex:outputPanel>
        </apex:repeat>
        <apex:outputText value="------------------------------------------------------------------" />
     </apex:repeat>
	        
</apex:form>
</apex:page>

Here is the controller class:

public class DynamicCaseLoader 
{
    public List<Contact> contactDetails 	{ get; private set; }

    public DynamicCaseLoader() 
    {
	String theQuery = 'SELECT id, name, title, phone, mailingcity, ReportsToID, ReportsTo.name, ReportsTo.email '+
               		   'FROM Contact';
        
        
        // Comment the following line of code and uncomment the line of code after that and the error will not occur.
        theQuery += ' WHERE ReportsToID = null';
        //theQuery += ' WHERE ReportsToID != null';

	contactDetails = Database.query(theQuery + ' LIMIT 50');
    }

    public List<contactFieldWrapper> contactFieldListObj 
    { 
        get {
            if (contactFieldListObj == null) 
            {
                contactFieldListObj = new List<contactFieldWrapper>();
                contactFieldListObj.add(new contactFieldWrapper('name'));
                contactFieldListObj.add(new contactFieldWrapper('title')); 
                contactFieldListObj.add(new contactFieldWrapper('phone')); 
                contactFieldListObj.add(new contactFieldWrapper('mailingcity')); 

                contactFieldListObj.add(new contactFieldWrapper('ReportsToID'));
                contactFieldListObj.add(new contactFieldWrapper('ReportsTo.name'));
                contactFieldListObj.add(new contactFieldWrapper('ReportsTo.email')); 
    
            }
            return contactFieldListObj;
        }
        private set;
    }

    public class contactFieldWrapper 
    {
        public String fieldName 	{ get; set; }
        public String sDisplayStyle  	{ get; set; }

        public contactFieldWrapper( String sName) 
        {
            fieldName = sName;
            sDisplayStyle = 'text-align:left;';
        }
    }
}

Now, any time you attempt to access the page, you will receive the following error:

Could not resolve field '' from <apex:outputField> value binding '{!contactObj[cf.fieldName]}' in page dynamiccaseeditor

If you comment line 12 and uncomment line 13 in the code, and attempt to access the page, you will NOT receive the error. (Make sure you have at least one contact with the ReportsToID field set.) This is because all the contacts displayed will have a value in the ReportsToID field and the outputField can properly resolve the value.

Other items of note:

• If you use outputText instead of outputField, everything works fine if the ReportsToID field is null.
• If you use a list of field names, instead of a list of class objects containing the field name, everything works fine if the ReportsToID field is null.
• With a more complex implementation (not this simple sample code), the error renders itself somewhat differently. Instead of the error message noted above, we receive an ‘Insufficient Privileges’ error.